rendleman



April 22, 1941. N. c. RENDLEMAN 2,239,203 METHOD OF: MAKING STEERINGKNUCKLES Original Filed July 9', 1958 2 sheets-sheet 1 INVENTOR I 4 MNormanCfiend/eman Z5 25' 25 April 1941- N. c. RENDLEMAN 2,239,203

METHOD OF MAKING STEERING KNUCKLES Original Filed July 9, 1938 2Sheets-Sheei 2 INVENTOR /I/0//77a/7 CZ M no/W278 kZM /LJZ atenteol Apr.22, 1941 METHOD OF MAKING STEERING KNUCKLES Norman C. Rendleman,Pittsburgh, Pa, assignor to Jones and Laughlin Steel Corporation, acorporation of Pennsylvania Original application July 9, 1938, SerialNo.

218,454. Divided and this amllication Novemher 18, 1940, Serial No.366,169

3 Claims. (Cl. 29-152) This invention relates to the manufacture offorged articles, and, in particular to a method of making steeringknuckles by rolling a bar of special shape in section and forging shortlengths thereof.

application, Serial No. 218,454 filed July 9, 1938, forForging blank forsteering knuckles.

Steering knuckles have been manufactured ?"5 This is a division carvedfrom my co-pendmg heretofore by a series of forging operations per-(Iformed on a work piece which is originally in the form of a short lengthof a billet of square section. The length is first reduced at one end toprovide a tong hold and is then subjected to a series of forgingoperations in a plurality of different shaping dies. Twelve forgingblows in all are necessary for making a forged knuckle by the priormethod and, of the weight of the initial work piece, forty-four per centis removed as scrap.

I have invented a novel method of making steering knuckles by forging,which is simpler, quicker and less costly than the former method. By myinvention, I am able to convert a blank into a forged steering knucklewith one or two forging blows and the amount of scrap to be removed isonly about fourteen per cent of the initial weight of the blank. In apreferred form, the blank comprises a short length of a rolled sectionof substantially Y-shape, the upper ends of the section being enlargedto provide spaced metal masses connected by a web of relatively reducedsection, with a rib or stem projecting from the web in the oppositedirection from said masses. The blank is formed by rolling a bar ofsuitable shape and cutting it into appropriate lengths. For a completeunderstanding of the invention, reference is made to the accompanyingdrawings illustrating a preferred embodiment and practice of theinvention. In the drawings:

Fig. l is an end View in perspective of a bar in accordance with myinvention adapted to provide a plurality of short lengths having metalmasses spaced appropriately for the forging of steering knuckles;

Fig. 2 is a side elevation of a forged steering knuckle with the forgingflash thereon;

Fig. 3 is a plan view of a finished steering knuckle;

Figs. 4 and 5 are side and end views thereof;

and

Figs. 6, 7, 8 and 9 show roughly the successive steps in the manufactureof the bar shown in Fig. 1.

Referring in detail to the drawings, the first step in the manufactureof steering knuckles, in

accordance with the invention, is the rolling of an elongated bar H] ofsuitable sectional shape to provide masses of metal appropriately spacedto fill the dies wherein steering knuckles are forged. As shown in Fig.Lthe bar Hi is roughly of Y-shape, the upper endsof the section beingenlarged as at H and i2, and connected by a relatively thin web I3.

A rib I l projects outwardly from the web lit in a direction oppositefrom the masses H and [2. The rib I 4 is disposed substantiallycentrally of the web it although not precisely so.

Considered in a slightly different light, the bar it might be'describedas a special bar the section of which is of generally Y-shape, widerthan it is deep, with enlarged, bulbous, upper extremities thicker thanthe mid-portion, and a rib extending downwardly from the mid-portion.Regardless of how the bar It is described, it will be recognized that itconstitutes roughly a channel section with flanges thickened adjacenttheir outer edges and a rib projecting outwardly from the web.

The bar It may be produced in convenient lengths by known methods of"rolling so it is unnecessary to make a detailed disclosure of thesuccessive rolling operations. It will suffice to refer to Figs. 6-9showing roughly the steps by which a billet of square section may bereduced by ordinary rolling procedure to a bar such as shown at Ill. Theimportant feature of this portion of the invention is that the center ofthe billet shown at 25, which contains the segregations and defects fromthe parent ingot is so distributed as shown in Fig. 9, that such defectsare almost obliterated and without adverse effect upon the resultingblank or the knuckle forged therefrom. This is in contrast to the priorpractice according to which the center of the billet extends axially ofthe knuckle spindle.

Short sections, of a length indicated by dotted lines l5, when out fromthe bar it, constitute blanks from which steering knuckles such as shownin Figs. 3 through 5 may readily be formed by one or two forgingoperations. Referring for a moment to the figures last mentioned, itwill :be observed that the knuckle there shown comprises a spindle l6and a yoke portion ll substantially at right angles thereto terminatingin bearing sockets I8 and [9 adapted to receive the king bolt of atilting wheel mounting. Lugs 23 extend outwardly from the sockets andare drilled as at 2| to receive bolts for securing the brake drum andassembly to the knuckle. The dotted lines in Figs. 3 through 5 show theportion of the forged knuckle that is removed in machining it toaccurate dimensions and performing other finishing operations thereon.

Fig. 2 shows a steering knuckle forged from a blank cut from a bar suchas shown at Ill, before the forging flash indicated at 22 has beentrimmed therefrom. The forged knuckle is produced by one or two blows ona blank such as that indicated generally at 23, by the forging dies usedheretofore to perform the finishing forging operation. A single blow ofsuch dies usually sufiices to reduce the blank 23 to the conditionillustrated in Fig. 2, although a second blow may be desirable in somecases. The shape of the blank 23 is such as to provide sufficient flashto cause the dies to fill fully and completely and to avoid cold shuts.It will be understood that the spaced masses ii and i2 provide metal forforming the bearing sockets i8 and I9 and the lugs 28. The web l3furnishes the metal necessary to form the yoke l4 while the rib or stemportion of the blank indicated at 24 furnishes the metal necessary toform the spindle Hi.

It will be noted that in forging the blank 23, the pressure exerted bythe dies is parallel to the rolling direction of the blank. Forgingblanks have heretofore been compressed between forging dies along a linetransverse to the rolling direction of the blank but I believe I am thefirst to adopt the procedure of disposing a' blank in the dies with itsdirection of rolling in the line along which forging pressure isexerted. This procedure appears to result in the production of a sounderand stronger forging than would be produced by the former practice.Forgings made by the prior practice exhibit irregular flow linesindicating excessive distortion. Forgings made in accordance with theinvention show smooth flow lines indicating a minimum distortionconsistent with the desired shaping effect.

When the forging shown in Fig. 2 has been subjected to a flash trimmingoperation, it is then ready for the machining and other finishingoperations necessary to convert it into final form;

as shown in Figs. 3 through 5.

It will be apparent that the invention is characterized by numerousadvantages over the previous method for the formation of steeringknuckles. is the great reduction in the amount of scrap which hasalready been mentioned, viz., from forty-four per cent by the old methodto about fourteen per cent by the practice described herein. which theknuckle is forged weighs less than the starting blank used in the priormethod. Likewise a greater number of blanks may be produced from a givenweight of metal. The reduction in the weight of the blank means that theblank can be heated more quickly, thus making it possible to obtaingreater production with the same blank heating equipment.

The reduction in the number of forging blows from fourteen under the oldmethod to one or two under the practice described is another highlyimportant advantage since it reduces the labor cost per unit as well asthe die cost. The wear on the dies per forging is reduced in proportionto the reduction in the number of blows and only a single set of dies isnecessary to convert the blank into a finished forging as compared withseveral sets used under the old method. The reduction in the number offorging blows required Perhaps the most important of these,

This means that the original blank from further increases the outputobtainable with existing forging equipment.

A further advantage of the invention has already been mentioned, viz.,the disposition of the defects of the parent ingot such as segregations,pipes, etc., which, despite all efiorts to the contrary, persist in theproduct of the final rolling, being located at the axial center of themass of metal regardless of its shape. Such defects are shownexaggerated in Figs. 6 through 9 at 25. The forging operations towhichthe blanks of my invention are subjected, bring the defective center tothe surface of the forging and tend to spread it along the length of theportion of the forging which is to form the yoke H of the finishedknuckle. The metal of which the spindle is formed is sound and free fromall defects.

In contra-distinction to the foregoing, the ingot defects carried overinto the billets used heretofore for forging knuckles remain unaffectedin about the same location, even after the final forging. Instead ofbeing brought to the surface of the yoke H, the defects lie at thecenter of the spindle portion of the knuckle Where they may 'seriouslyimp-air the strength of the finished knuckle.

Blanks for various designs of knuckles may be made of bars differingsomewhat in shape from the bar Hi, depending on the requirements of any0 given design of knuckles.

Although I have illustrated and described but a preferred embodiment andpractice of the invention, it will be understood that changes in thearticle or procedure disclosed may be made without departing from thespirit of the invention or the scope of the appended claims.

I claim:

1, In a method making a steering knuckle having spaced, alined bearingsockets connected by a yoke portion from which a spindle extendslaterally, the steps including rolling a long bar generally Y-shaped insection, having bulbous enlargements adjacent the ends of the forkedportion and a tape-ring rib forming the stem of the Y, severing the barinto short lengths and subjecting one of the lengths to die forgingblows thereby forming said enlargements into said sockets and said ribinto said spindle, while shaping the metal between said enlargements andsaid rib to form said yoke.

2. In a method of making a steering knuckle having spaced, alinedbearing sockets connected by a yoke portion from which a spindle extendslaterally, the steps including rolling a. long bar generally Y-shaped insection, having bulbous enlargements adjacent the ends of the forkedportion and a tapering rib forming the stem of the Y, severing the barinto short lengths, and subjecting one of the lengths to die forgingblows relatively small in number compared to the number necessary toforge a knuckle from plain stock, thereby forming said enlargements intosaid sockets and said rib into said spindle, while shaping the metalbetween said enlargements and said rib to form said yoke.

3. The method of making steering knuckles, which comprises rolling a barY-shaped in section having flanges connected by a Web, the flanges beingthicker than the web and having a tapered rib projecting from the web,cutting the bar into short lengths, and forging said lengths intosteering knuckles.

NORMAN C. RENDLEMAN.

